The term plasmid was first introduced by the American molecular biologist Joshua Lederberg in 1952.[1] Plasmid sizes vary from 1 to over 1,000 kbp.[2] The number of identical plasmids in a single cell can range anywhere from one to thousands under some circumstances. Plasmids can be found in all three major domains: Archaea, Bacteria, and Eukarya.[3]